A method for preparing alpha sources of polonium. A sample of polonium is provided in a solution. A controlled amount of sulfide and a controlled amount of a metal capable of forming an insoluble sulfide salt in the solution are introduced into the solution, in order to co-precipitate polonium from the solution. The precipitates are filtered out.

A method for preparing alpha sources of polonium. A sample of polonium is provided in a solution. A controlled amount of sulfide and a controlled amount of a metal capable of forming an insoluble sulfide salt in the solution are introduced into the solution, in order to co-precipitate polonium from the solution. The precipitates are filtered out.

In certain embodiments, a first semiconductor material is vaporized to generate a vapor phase condensate. The vapor phase condensate is allowed to form nanoparticles. The nanoparticles are annealed to yield nanoparticles or cores. The cores are overcoated by introducing a solution containing second semiconductor material precursors in a coordinating solvent into a suspension of cores at a desired elevated temperature and mixing for a period of time sufficient to cause diffusion of the shell into the core. The diffusion of the shell into the core causes the quantum dots to exhibit a broadened optical emission. The produced quantum dots may be incorporated into a quantum dot based radiation source.

The present invention relates to a method for controlling the density of an amorphous sulfide and, more specifically, to a method for producing an amorphous sulfide having high ionic conductivity of lithium ions by controlling the interplanar distance between a metal atom and a chalcogen atom through the adjustment of the reaction temperature and rate, in carrying out a sulfidation reaction by supplying a sulfur source in a gas phase onto the surface of a metal or an alloy.

The present invention relates to a method for controlling the density of an amorphous sulfide and, more specifically, to a method for producing an amorphous sulfide having high ionic conductivity of lithium ions by controlling the interplanar distance between a metal atom and a chalcogen atom through the adjustment of the reaction temperature and rate, in carrying out a sulfidation reaction by supplying a sulfur source in a gas phase onto the surface of a metal or an alloy.

A nanocrystal preparation method comprises the following steps: dissolving, in a first selected solvent, a first precursor which is in a gaseous state under normal temperature and normal pressure, to form a first precursor solution; dissolving a second precursor in a second selected solvent to form a second precursor solution, wherein the second precursor is a precursor of a metal element of Group I, Group II, Group III or Group IV; and in an inert gas atmosphere, adding the first precursor solution into a reaction vessel which contains the second precursor solution, wherein the first precursor chemically reacts with the second precursor to generate a nanocrystal. The present invention further discloses a nanocrystal prepared by the above method and an apparatus for preparing and storing a gas-dissolved solution. With the preparation method according to the invention, the amount of the first precursor in a gaseous state can be accurately controlled, the reaction is more uniform and more controllable, and the obtained nanocrystal has uniform volume distribution and a higher luminescent quantum yield.

A nanocrystal preparation method comprises the following steps: dissolving, in a first selected solvent, a first precursor which is in a gaseous state under normal temperature and normal pressure, to form a first precursor solution; dissolving a second precursor in a second selected solvent to form a second precursor solution, wherein the second precursor is a precursor of a metal element of Group I, Group II, Group III or Group IV; and in an inert gas atmosphere, adding the first precursor solution into a reaction vessel which contains the second precursor solution, wherein the first precursor chemically reacts with the second precursor to generate a nanocrystal. The present invention further discloses a nanocrystal prepared by the above method and an apparatus for preparing and storing a gas-dissolved solution. With the preparation method according to the invention, the amount of the first precursor in a gaseous state can be accurately controlled, the reaction is more uniform and more controllable, and the obtained nanocrystal has uniform volume distribution and a higher luminescent quantum yield.

A porous membrane comprising stacked layers of nanosheets, each nanosheet comprising one to three atomic layers of a 2D material comprising or consisting of one or more transition metal dichalcogenides is provided. The nanosheets have pores and the membrane comprises a network of water permeation pathways including through-pathways formed by the pores, horizontal pathways formed by gaps between the layers, and vertical pathways formed by gaps between adjacent nanosheets and stacking defects between the layers. Also provided is a method for making the membrane.

A method of producing an organopolysulfide or salt thereof is provided which includes a step of mixing an organomonosulfide or salt thereof and elemental sulfur, wherein the mixing is carried out at a temperature not greater than 95 C and in the absence of any added liquid phase for a time effective to produce the organopolysulfide or salt thereof. The described method makes possible the preparation of organopolysulfides and organopolysulfide salts without the use of solvent or catalyst.

A method of producing an organopolysulfide or salt thereof is provided which includes a step of mixing an organomonosulfide or salt thereof and elemental sulfur, wherein the mixing is carried out at a temperature not greater than 95 C and in the absence of any added liquid phase for a time effective to produce the organopolysulfide or salt thereof. The described method makes possible the preparation of organopolysulfides and organopolysulfide salts without the use of solvent or catalyst.